Exemplary embodiments of the present invention relates to a radar apparatus for measuring a distance to a target and a velocity of a target, and more particularly, to a radar apparatus which features improved reliability than an analog scheme using a digital modulation and demodulation technology and is easily implemented with an integrated circuit technology.
Background Art of the present invention is disclosed in Korean Patent Laid-Open Publication No. 2009-0067990 (Published in Jun. 25, 2009).
Recently, as a demand for a short range high resolution radar is increased in a millimeter/sub-millimeter band, a study thereof has been continued. The high resolution radar system capable of discriminating or decomposing a distance between proximity objects has been variously used as industrial, military applications, and the like, and has been mainly used for a radar system for a vehicle in a real life. The radar system for a vehicle, which is an essential technology for implementing an intelligent traffic system, may mean a safety driving system of a vehicle developed so as to previously prevent accidents occurring due to poor weather conditions or carelessness of a driver by sensing motions of other vehicles or objects that move or stop.
A radar in a frequency modulation continuous wave (FMCW) scheme in accordance with the related art frequency-modulates and transmits a transmitting signal into a type (for example, a triangular wave) of linearly increasing and reducing a frequency of the transmitting signal over time. In the related art, a receiver receives an echo signal returned due to reflection of the transmitting signal from the target prior to a predetermined time to obtain a beat frequency corresponding to a difference in frequencies between the transmitting signal and the echo signal and obtains position and velocity information of a target using the obtained beat frequency. An example of the FMCW scheme may include an analog modulation scheme as a scheme for obtaining the beat frequency. However, the analog modulation scheme has lower reliability than a digital scheme, which is not suitable to use developed integrated circuit technologies. Further, when a number of radars simultaneously use a frequency in the same band, mutual interference occurs in signals, which may lead to degradation in receiving performance.